News

In the sequel of a long list of workshops organized by IST, MARIN (see http://www.refresco.org/verification-validation/vv-workshops/ for a full list, and links), next year May 2017, in LasVegas, Nevada, USA, a new Workshop on Iterative Errors in Unsteady Simulations will be organized under the ASME V&V 20 Committee activities. MARIN and IST will be organizing it and […]

Last end of May, ReFRESCO has been installed in the clusters of Texas A&M University, College Station, USA. Also, an introductory course has been given to some interested Msc, Phd, Post-docs and staff members of TAMU. And a general presentation on the past, present and future of ReFRESCO has also been done. We expect a very […]

Events

May 3, 2017 – V&V Workshop (ASME V&V 20)Next year May 2017, in LasVegas, Nevada, USA, a new Workshop on Iterative Errors in Unsteady Simulations will be organized under the ASME V&V 20 Committee activities. ReFRESCO, and some of its developers, will be organizing it and also participating with results. Some international members of the committee already showed the intention to participate actively […]

May 15, 2017 – ECCOMAS Marine 2017ReFRESCO users and developers will organize an Invited Session, and present several papers to the ECCOMAS Marine 2017 conference to be held in Nantes, France, May next year. The objective of Marine 2017 (http://congress.cimne.com/marine2017/frontal/default.asp) is to be a meeting place for researchers developing computational methods and scientists and engineers focusing on challenging applications in marine […]

@conference{2016-NUTTS_Lemaire_et_al_Transition,
title = {Modelling Natural Transition on Hydrofoils for Application in Underwater Gliders},
author = {Sebastien Lemaire and Artur K. Lidtke and Guilherme Vaz and Stephen R. Turnock},
url = {http://www.refresco.org/download/2016-nutts_lemaire_et_al_transition/},
year = {2016},
date = {2016-10-03},
address = { St. Pierre d'Oléron, France},
organization = {NUTTS},
abstract = {Underwater gliders are a class of autonomous underwater vehicles (AUV) used for long-endurance missions. They employ a buoyancy engine in order to induce vertical motion through the water column and by adopting an appropriate trim angle they propel themselves forward using hydrofoils. The velocities these vessels reach are typically less than 0.5m/s. Efficiency of their hydrofoils is of course a key factor determining the overall system performance. Therefore, better understanding the nature of transition occurring on these foils is of significant importance for the design of next generation underwater gliders. Standard turbulence models are known to predict transition onset too early in terms of Reynolds number, mainly because they were first developed with applications to fully turbulent flows in mind (Rosetti et al., 2016). For this reason a range of models designed to predict transition have been introduced in the literature (Van Ingen, 2008).
The aim of this paper is to assess the usefulness of the Local Correlation Transition Model (LCTM, also known as gamma - Reg, Langtry and Menter, 2009), implemented in the finite volume solver ReFRESCO (Rosetti et al., 2016), for application to engineering problems involving laminar and transitional Reynolds number regimes. The study will be focusing on modelling the flow around 3D infinite foils and underwater glider swept hydrofoils to analyse transition to turbulence as well as the nature of the separation bubble. Development of a better understanding of these phenomena will help to achieve a more efficient design in the future.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}

Underwater gliders are a class of autonomous underwater vehicles (AUV) used for long-endurance missions. They employ a buoyancy engine in order to induce vertical motion through the water column and by adopting an appropriate trim angle they propel themselves forward using hydrofoils. The velocities these vessels reach are typically less than 0.5m/s. Efficiency of their hydrofoils is of course a key factor determining the overall system performance. Therefore, better understanding the nature of transition occurring on these foils is of significant importance for the design of next generation underwater gliders. Standard turbulence models are known to predict transition onset too early in terms of Reynolds number, mainly because they were first developed with applications to fully turbulent flows in mind (Rosetti et al., 2016). For this reason a range of models designed to predict transition have been introduced in the literature (Van Ingen, 2008).
The aim of this paper is to assess the usefulness of the Local Correlation Transition Model (LCTM, also known as gamma - Reg, Langtry and Menter, 2009), implemented in the finite volume solver ReFRESCO (Rosetti et al., 2016), for application to engineering problems involving laminar and transitional Reynolds number regimes. The study will be focusing on modelling the flow around 3D infinite foils and underwater glider swept hydrofoils to analyse transition to turbulence as well as the nature of the separation bubble. Development of a better understanding of these phenomena will help to achieve a more efficient design in the future.

@conference{2016-IFAC-CAMS2016_Ramirez_et_al,
title = {Hydrodynamic modelling for the remotely operated vehicle Visor3 using CFD},
author = {Juan Ramirez-Macias and Persijn Brongers and Santiago Rua and Rafael Vasquez},
url = {http://www.refresco.org/download/2016-ifac-cams2016_ramirez_et_al_cfdmodellingvisor3/},
year = {2016},
date = {2016-09-13},
address = {Trondheim, Norway},
organization = {IFAC CAMS2016},
abstract = {This paper addresses the hydrodynamic modelling of an inspection-class remotely operated vehicle using a viscous- flow solver for the accurate prediction of manoeuvring coefficients needed for control purposes. The 6-DOF dierential nonlinear equation of motion for the ROV visor3 is first described with emphasis on hydrodynamic terms. Then, the hydrodynamic model of the ROV is assembled from data obtained using the Virtual Captive Test (VCT) approach, where experiments such as the Planar Motion Mechanism (PMM) are simulated using CFD. In this work, the Maritime Research Institute Netherlands' viscous flow solver ReFRESCO is used to solve the steady-state and unsteady Navier-Stokes equations for single-phase turbulent incompressible flow, using a detailed geometry of the ROV. Three scenarios are considered: steady-state computations of forces and moments for different values of inflow velocity's direction, steady-state computations of forces and moments for circular manoeuvres on the XY plane, and unsteady computations of forces and moments for rotation around the XYZ axes. The computation of manoeuvring coefficients using CFD allows one to develop a preliminary mathematical model for control purposes when there are limitations for performing physical tests.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}

This paper addresses the hydrodynamic modelling of an inspection-class remotely operated vehicle using a viscous- flow solver for the accurate prediction of manoeuvring coefficients needed for control purposes. The 6-DOF dierential nonlinear equation of motion for the ROV visor3 is first described with emphasis on hydrodynamic terms. Then, the hydrodynamic model of the ROV is assembled from data obtained using the Virtual Captive Test (VCT) approach, where experiments such as the Planar Motion Mechanism (PMM) are simulated using CFD. In this work, the Maritime Research Institute Netherlands' viscous flow solver ReFRESCO is used to solve the steady-state and unsteady Navier-Stokes equations for single-phase turbulent incompressible flow, using a detailed geometry of the ROV. Three scenarios are considered: steady-state computations of forces and moments for different values of inflow velocity's direction, steady-state computations of forces and moments for circular manoeuvres on the XY plane, and unsteady computations of forces and moments for rotation around the XYZ axes. The computation of manoeuvring coefficients using CFD allows one to develop a preliminary mathematical model for control purposes when there are limitations for performing physical tests.